Crank link extractor for gun



Feb. 25, 1958 w. D. BOBCO ETAL 2,824,401

CRANK LINK EKTRACTOR FOR GUN 2 Sheets-Sheet 1 Filed April 5, 1954 IN V EN TORS H TTOENE Y5 CRANK LINK EXTRACTOR FOR GUN William D. Bobco, Berwyn, and Eugene S. Wassel, Cicero, Ill., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Army Application April 5, 1954, Serial No. 421,209

6 Claims. (Cl. 42-68) Our invention relates to an electrically-fired revolvertype automatic gun and more particularly to an extractor therefor.

Such a gun ordinarily comprises a recoil unit slidably disposed on a receiver and provided with a barrel. The recoil unit also includes a drum having spaced cartridge chambers and corresponding index rollers.

The drum is rotatably mounted on the recoil unit and an actuator having grooves for successively engaging the rollers is slidably disposed on the receiver to rotate the drum and sequentially convey the cartridge chambers to positions including a six oclock firing position of the drum aligned with the barrel.

In one rotation of the usual cartridge drum of five chambers, each of the chambers dwells successively in four nonfiring positions while the cartridges in the remainder of the chambers are fired. Cartridges are inserted in the chambers in two stages in a pair of the dwell positions of the drum and the cases of the spent cartridges are removed from the drum in an extraction position immediately following the firing position.

The actuator guide groove of the gun retains the drum at rest rotationally during the initial substantially twoinch portion of rearward travel from battery position and consequently there is no rotation of the drum for a comparable final portion of the actuator forward stroke. The case of the spent cartridge is generally removed from the drum in this final portion of the actuator forward stroke.

The extractor of the gun includes a pawl constructed to extend into the extractor groove of a case chambered in the extraction position and biased to the rear face of the drum by a piston spring. The pawl is displaced rearwardly to extract the case from the drum responsive to the actuator in the final portion of the forward stroke of one cycle and the pawl remains displaced during the initial portion of the forward stroke of the succeeding cycle, at the end of which the piston spring returns the pawl to engagement with the rear drum face. The period required for this return determines the maximum rate of operation of the gun.

It is readily seen from the description that no useful purpose is accomplished by allowing the pawl to remain displaced from engagement with the drum face during the initial portion of the succeeding rearward stroke of the actuator since extraction is completed before the actuator returns to battery position. If the extractor were freed from the actuator at the end of extraction, a greater proportion of the gun cycle would be available for the piston spring to return the pawl to engagement with the drum face and consequently the rate of fire of the gun could be increased.

It is an object of our invention, therefore, to provide an extractor for the gun described that is responsive to the actuator in the forward stroke thereof only.

Another object of our invention is to provide an extractor for smoothly imparting an increasing pair of velocities 2,824,401 l atented Feb. 25, 1958 to a spent cartridge case during extraction thereof from such a gun.

A further object of our invention is to provide an extractor for an automatic gun having a sliding lever for imparting a pair of increasing velocities to a case during removal thereof from the gun.

Other aims and objects of our invention will be evident from the following explanation.

In carrying out our invention, a piston having a flange is mounted on the recoil unit, a pawl for engaging the extractor groove of a case chambered in the extraction position is pivoted and biased to a normal position on the flange and the piston is spring-loaded to bias the pawl against the rear face of the drum. A lever, pivoted on a shaft journaled in the recoil unit, engages the piston and is responsive to the actuator in the forward stroke thereof to operate the pawl for case extraction. The recoil unit is provided with a fulcrum for engagement with an intermediate point on the arm of the lever and the pivot hole of the lever is elongated to permit a change in instantaneous center of the lever in rotation about the shaft, to increase the extraction velocity of the case. A crank, mounted on the shaft, includes a lug for engaging the actuator and a pin for engaging the lever in the forward stroke of the actuator.

For a more complete understanding of our invention, attention is directed to the following description and accompanying drawing in which:

Fig. 1 is a partly broken away elevation view of the drum and extraction device of an automatic gun incorporating our invention;

Fig. 2 is a view along line 22 of Fig. 1; and

Fig. 3 is an interior exploded viewof the extractor mechanism from the left side.

According to the drawing, a gun 12 includes a recoil unit 14 and an actuator 16, respectively, slidable on a receiver 18 by means of feet 20 and 22.

A barrel 23 is secured to recoil unit 14 and a drum 24 is rotatably mounted on a shaft 26 journaled in the recoil unit. Drum 24 includes spaced cartridge chambers, a pair of which are shown in the six oclock firing position 28 of the drum aligned with barrel 23, and in an extraction position 30 of the drum immediately following the firing position. Spent cartridge case 31 is shown in extraction position chamber 30.

Recoil unit 14 includes a cylinder 32 having a piston 34 slidably disposed therein and biased to a forward position by a spring 36. A flange 38 of the piston slides in a slot 40 through cylinder 32 and a pawl 42 is pivoted on flange-38 by means of a pin 44. Pawl 42 is biased to a normal position against a stop portion 46 of flange 38 by a spring 48. In the forward position of piston 34, pawl 42 extends along rear face 50 into the extractor groove 52 of case 31. r

A shaft 54 extends through an elliptical slot 56 in a lever 58 and through a bearing 60 in recoil unit 14. Lever 58 includes projecting arms 62 and 64 with arm 62 extending for engagement with a shoulder 63 of flange 38. A fulcrum 65 is provided on recoil unit 14 to engage arm 62 and allow piston spring 36 to bias lever 58 into normal engagement with shaft 54 at one end 66 of slot 56. A crank 67, secured to shaft 54, includes a lug 68 for engaging va striker 7t! projecting from actuator 16. A pin 72 projects from lug 68 for engagement with arm 64.

' A post 74 is provided on recoil unit 14 and a spring 76, wrapped around shaft 54 and secured between a hole 78 in the shaft and post 74, biases pin 72 against arm 64.

As actuator 16 moves rearwardly (to the right in Fig. 3) responsive to discharge of a cartridge chambered in firing position 28, pin 72 is rotated against spring 76 and striker passes beneath the pin. As actuator16 mechanism of the gun. .smoothsince the change of instantaneous centers of the 3 Continues ,rearwardly, pin 72 is returned to contact with arm 64 by spring 76.

On the forward stroke of actuator 16, striker 70 engagesilug .68 to pivot crank 58 on fulcrum 65 and, begin extraction of case 31 from drum 24. As leverz53 rotates, the aopposite end 80 of slot 56 engages shaft 54 to pivot lever 58 therearound and decrease the mechanical advantage of lever 58 to accelerate the movement of the case from the drum. Pawl 42 pivots for disengagement .from case 31 at the end of stroke of piston 34.

As actuator 16 continues forwardly to battery position, striker 70 passes beneath lug 68 to permit piston spring 36 to successively return arm 62 to engagement with fulcrum 65 and end 66 to engagement with shaft 54. ,Arm 64 rerotates crank 67 by engagement with pin 72.

'With' the mechanism described above, the extraction force is applied at a comparatively slowrate to dislodge a spent cartridge case from drum 24 and the velocity of :the caseis increased during the later portion of the extraction stroke to permit the case to clear the feeder Operation of the extractor is lever is accomplished without interruption of the extracparallel to the axis of the shell. The extractor is responsive to the actuator during a portion of the forward stroke thereof only, allowing a larger proportion of the actuator cycle for restoration of the pawl to engagement with the drum face.

While the foregoing is a description of the preferred embodiment, the following claims are intended to include those modifications and variations that are within the spirit and scope of our invention.

We claim:

1. A cartridge extraction device for a revolver-type automatic gun, including a recoil unit, a drum provided with cartridge chambers and rotatably disposed on the recoil unit, and an actuator slida'ble with respect to the recoil unit for rotating the chambers to positions thereof including an extraction position, said device comprising a pivoted on said piston and spring-biased against said stop for engagement with the rear face of the drum and for extending into the extractor groove of a case chambered in the extraction position, and means for moving said pawl rearwardly to extract the case from the drum responsive to forward movement of the actuator, including a shaft journaled in the recoil unit, a fulcrum secured thereto, and a lever for engaging said piston having an elliptical slot enclosing said shaft, said'lever being adapted to successively ivot on said fulcrum and said shaft during said forward movement to transmit an increasing pair of velocities to the case.

2. A cartridge extraction device for a revolver-type automatic gun, including a recoil unit, a drum provided with cartridge chambers and rotatably disposed on the recoil unit, and an actuator slidably disposed with respect to the recoil unit for rotating the chambers to an extraction position, said extraction device comprising a striker secured to the actuator, a recoil unit cylinder having a piston slidably disposed therein provided with a stop and biased forwardly, a pawl pivoted on said piston and springbiased against said stop for engagement with the rear face of the drum and for projection into the extractor groove of a case chambered in the extraction position, and means for moving said pawl rearwardly to extract the case from the drum responsive to forward movement of the actuator, including a shaft journaled in the recoil unit, a fulcrum secured to the recoil unit, a lever for engaging said piston having an elliptical slot enclosing said shaft, and a crank secured to said shaft provided with an arm for engaging .said striker and a pin for successively pivoting said lever on said fulcrum and said shaft during said rotation to apply an increasing pair of extraction velocities to the case.

.3.,A cartridge extraction device for a revolver-type automatic gun, including a recoil unit, a drum provided with cartridge chambers and rotatably disposed on the recoil unit, and an actuator slidably disposed with respect to the recoil unit for rotating the chambers to an extraction position, said extraction device comprising a striker secured to the actuator, a recoil unit cylinder having a piston slidably disposed therein including a pawl for engagement with the rear face of the drum and for projecting into the extractor groove of a case chambered in the extraction position and a spring for biasing said piston forwardly, a crank and a lever pivoted on said recoil unit, said lever having a pair of arms including an arm for engaging said piston, and said crank having a pin for engaging the other of said arms and a lug for engaging said striker to pivot said lever and extract the case from the drum responsive to forward movement of the actuator, said striker being adapted for disengagement from said lug before the actuator returns to the battery position thereof.

4. A cartridge extraction device for a revolver-type automatic gun including a recoil unit, a' drum with cartridge chambers rotatably disposed on the recoil unit, an actuator slidable in rearward and forward stroke operation with respect to the recoil unit for rotation of the chambers to firing and extraction positions responsive to discharge of cartridges chambered in the firing position, said device comprising a recoil unit cylinder with a slidable piston provided with a pawl and spring-biased to a forward position for engagement of said pawl with. the extractor groove of a cartridge chambered in the extraction position, and a lever for engaging said piston disposed on the recoil unit for pivoting about a pair of instantaneous centers to operate said piston and remove the case from the drum at an increasing pair of extraction velocities responsive to the forward stroke.

5. A cartridge extraction device'for a revolver-type automatic gun, including a recoil unit, a drum provided with cartridge chambers and rotatably disposed on the recoil unit, and an actuator slidable in rearward and forward stroke operation with respect to the recoil unit for rotating the chambers to positions thereof including adjacent firing and extraction positions responsive to discharge of cartridges chambered in the firing position, said device comprising a recoil unit cylinder, a piston slid ably disposed therein provided with a stop and biased to a forward position, a pawl pivoted on said piston and spring-biased against said stop for normal position engagement with the extractor groove of a case chambered in the extraction position, a shaft and a pin respectively journaled and secured in the recoil unit, and a level for engaging said piston having an elliptical slot enclosing said shaft, to successively pivot on said pin and said shaft and transmit an increasing pair of velocities to the case responsive to said forward stroke.

6. Intan automatic gun including a recoil unit, a drum rotatably disposed thereon and provided with chambers for cartridges, an actuator in the recoil unit biased to a battery position and disposed for slidable operation in rearward and forward strokes for rotation of the chambers to afiring position for discharge of the cartridges and to an extraction position responsive to the discharge, and piston means biased to a forward position and provided with a pawl pivoted thereon and biased to a normal positionfor projection into the extractor grooves of cartridges chamberedinthe extraction position, a device in the recoil unit provided with a lever disposed to engage the piston means and successively pivoted about a pair of centers in the recoil unit to remove the cases from the drum at an increasing pair of extraction velocities responsive to the forward strokes, said device being disposed for battery position disengagement from the actuator for return of the pawl toithenormal position.

' (References on following page) References Cited in the file of this patent UNITED STATES PATENTS Richmond Dec. 8, 1896 Vickers Oct. 29, 1946 Stevens et a1. Oct. 27, i953 6 Schneider May 24, 1955 Runge Jan. 15, 1957 FOREIGN PATENTS Ita'Iy Mar. 16, 1945 Great Britain June 24, 1953 

